This invention relates to an electronic counter circuit for use in a tape recorder etc.
In general, a tape recorder includes a tape counter representing an amount of tape travel. In the prior art, a mechanical type counter has been primarily used in which a digit board rotates in interlock with the rotation of a reel shaft and which displays a corresponding count value. Recently, however, an electronic counter circuit is used which counts pulses generated according to the rotation of the reel shaft and displays a corresponding count value. The electronic counter circuit can effect various controls using count values. When the running of the tape reaches a predetermined count value during the fast forward or rewind mode it is possible to automatically stop the running of the tape. Since the display section of the electronic counter circuit dissipates much power, it is desirable that the electronic counter circuit be disconnected from the power supply at the time of the stopping of tape travel. However, the running of the tape is temporarily stopped when switching is made from the playback mode to the rewind mode, resetting the counter and thus erasing a count value on a display section. For this reason, in the prior art devices the count value corresponds to an amount of tape travel as measured from each stopping position of the tape, not an absolute amount of tape travel as measured from the initial position where the tape is fully wound on one reel shaft. One approach to this problem is to provide a display switch separately from the operation switch of the tape recorder so that a supply of a power supply voltage to the display section can be controlled. This approach complicates an arrangement involved, there being a risk that a count value on the display section will be erased by an erroneous operation of the additional switch. The count value of the counter is stored in the memory to which a power supply voltage is supplied at all times. However, there are the cases where it is desired to reset the counter for the replacement of the tape and so on. In order to attain this object a reset switch is provided, but even in this case there is a possibility that the counter will be reset, like the display switch, by the erroneous operation of the reset switch.